A061227 -id:A061227 - cp's OEIS frontend

A068396 n-th prime minus its reversal.

0, 0, 0, 0, 0, -18, -54, -72, -9, -63, 18, -36, 27, 9, -27, 18, -36, 45, -9, 54, 36, -18, 45, -9, 18, 0, -198, -594, -792, -198, -594, 0, -594, -792, -792, 0, -594, -198, -594, -198, -792, 0, 0, -198, -594, -792, 99, -99, -495

Offset: 1

Reinhard Zumkeller, Mar 08 2002

a(n) = 0 for n in A075807. - Michel Marcus, Sep 27 2017

All terms are divisible by 9. - Zak Seidov, Jun 05 2021

			a(10) = 29 - 92 = -63;
a(20) = 71 - 17 = 54.

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Cf. A000040, A004086, A056965, A061227, A075807.

a068396 n = p - a004086 p  where p = a000040 n
-- Reinhard Zumkeller, Feb 04 2014

#-IntegerReverse[#]& /@ Prime[Range[50]] (* Harvey P. Dale, Dec 20 2012 *)

a(n) = prime(n) - fromdigits(Vecrev(digits(prime(n)))); \\ Michel Marcus, Sep 27 2017

from sympy import prime
def a(n): pn = prime(n); return pn - int(str(pn)[::-1])
print([a(n) for n in range(1, 50)]) # Michael S. Branicky, Jun 05 2021

a(n) = A000040(n) - A004087(n).

a(n) = A056965(A000040(n)). - Michel Marcus, Sep 27 2017

A344871 a(n) is the least number that can be represented in exactly n ways as the sum of a prime and its digit reversal.

Original entry on oeis.org

1, 4, 44, 88, 1090, 3212, 4334, 2992, 5995, 4994, 7997, 9779, 5104, 11110, 11891, 10109, 11000, 10780, 108880, 110500, 252142, 278872, 296692, 293282, 308902, 287782, 411103, 289982, 466664, 281072, 457754, 398893, 298892, 462154, 517814, 494384, 299992, 707806, 471064, 476674, 487784, 467764

Offset: 0

J. M. Bergot and Robert Israel, May 31 2021

If the reversal of p is another prime, p+reversal(p) and reversal(p)+p are both counted.

a(n) is the first number that occurs exactly n times in A061227.

			a(4) = 1090 because 1090 = 149+941 = 347+743 = 743+347 = 941+149, and this is the least number with exactly four such representations.

Robert Israel, Table of n, a(n) for n = 0..92

Cf. A004086, A061227, A056964.

revdigs:= proc(n) local L,t;
L:= convert(n,base,10);
add(L[-t]*10^(t-1),t=1..nops(L));
end proc:
V:= Vector(10^6):
p:= 1:
do
  p:= nextprime(p);
  if p > 9*10^5 then break fi;
  r:= p+revdigs(p);
  if r <= 10^6 then V[r]:= V[r]+1 fi
od:
A:= Array(0..64):
for i from 1 to 10^6 do
  if V[i] <= 64 and A[V[i]] = 0 then A[V[i]]:= i fi
od:
convert(A,list);

cp's OEIS Frontend

A068396 n-th prime minus its reversal.

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